This disclosure relates to wireless communications.
Wireless communication devices can use one or more wireless communication technologies such as orthogonal frequency division multiplexing (OFDM) or code division multiple access (CDMA). In an OFDM based wireless communication system, a data stream is split into multiple data substreams. Such data substreams are sent over different OFDM subcarriers, which can be referred to as tones or frequency tones. Various examples of wireless communication devices include mobile phones, smart phones, wireless routers, wireless hubs, base stations, and access points. In some cases, wireless communication electronics are integrated with data processing equipment such as laptops, personal digital assistants, and computers.
A wireless communication device can generate a transmission signal based on two or more constituent signals. A signal transmitted over a wireless communication channel may be subject to channel noise such as additive white Gaussian noise (AWGN), Rayleigh fading, or even blockage. To decode a received signal, a device can use information based on characteristics of a constituent signal and one or more channel measurements. In some cases, constituent signals can be encoded using channel encoders of different rates and with different amounts of redundancies. Moreover, constituent signals can be modulated using different signal constellations, respectively. Various examples of coding techniques include Reed-Solomon coding, convolutional coding, and turbo coding. Various examples of modulation techniques include quadrature amplitude modulation (QAM) and pulse amplitude modulation (PAM).
A wireless communication device can perform successive interference cancellation (SIC) ordered decoding to process a received signal that is based on multiple constituent signals. A SIC ordered decoding technique includes detecting the strongest signal by assuming other interfering signals to be Gaussian, decoding the strongest signal, re-encoding and re-modulating the decoded signal, and subtracting the re-modulated signal from the received signal to produce a modified received signal. The next strongest signal is then similarly decoded based on the modified received signal. These operations repeat until all of the constituent signals are decoded. A SIC ordered decoding technique can perform a maximum likelihood (ML) detection over individual signal constellations that are associated with respective constituent signals.